Officially a committee can jail refuseniks for contempt, but the power has remained untested in recent times and was last exercised more than 50 years ago. Critics say this allows those who do not wish to appear before a committee an easy out.

In parliament on Thursday, Bryant said many felt select committee powers are “unclear” and that witnesses increasingly “call our bluff.”

He cited a committee report from 2013 which recommended changes “to make it absolutely clear that parliament can arrest, punish and fine offenders and said that ‘if the problems we have identified ... are not resolved ... today’s parliament should stand ready to legislate.’”

He said nothing had been done to speed up that process and that it is time to make it a “criminal offence to fail to appear or refuse to appear, without reasonable excuse, before a committee of this house.”

Tory Leader of the House of Commons Chris Grayling agreed with Bryant’s call for reflection on the issue.

What went unmentioned, however, was Cameron’s announcement Wednesday that he would not be appearing before a committee inquiry on the Libyan war.

In his written statement to the Foreign Affairs Committee chair Crispin Blunt, Cameron claimed he was too busy and that the inquiry had enough evidence from other government sources to keep it busy.

Should powers to prosecute committee no-shows be extended, the prime minister could be found in contempt.